Should have brought a pulse-ox with you. Be curious to see how low it went.
When I did the "fly the simulator with hypoxia" ROBD ride a few years ago, I want to say mine got way down to 50-60 (lower than they meant, ha ha). The Navy had just started doing those in the wake of the OBOGS/physiological episode scandal.
The profile I flew was a standard course rules departure into an ILS, about 10-15 minutes. The AMSO was there with the machine and reading off the saturation numbers and the sim guy was there to run the sim. I remember getting kind of a brain fog and graying out but the profile and procedures were so second nature that I flew the plane well enough that I didn't crash the sim. What I remember most was the feeling of physical distress, not just the confusion and sweating a bit but a really bad feeling. Funny thing was I blacked out right before touchdown, perfect timing because I must have put a bit of a flare in (and not crash the sim...), right as the doc announced the latest number and spun the control knob the other way so I could get oxygen again. I came to a couple thousand feet into the roll, still confused but not so bad that I couldn't remember to hit the brakes and bring it to a stop on the runway.
All good fun, especially how they let me get a bit lower than they meant, fun not crashing the sim too (booyah!), but the physicality of it really stuck with me. I don't remember that from the API chamber ride at all.
At the time, the Navy aeromedical and aviation physiology commuting was figuring out a ton of stuff about how your body gets oxygen to your brain and how all those processes work with the equipment in Uncle Sam's aircraft. That extra work going on was part of the OBOGS fallout.
(ROBD is the thing that dilutes your breathing air with nitrogen. That simulates
some high altitude effects by reducing the partial pressure of oxygen in your lungs.)
It was a pretty great experience that built a lot on the chamber ride and four-year recurrent survival/physiology training. I have the VT-J instructors/Kingsville and Meridian JOPA, who collectively put their foot down in the spring of 2017, to thank for it.